U.S. patent number 5,103,043 [Application Number 07/672,209] was granted by the patent office on 1992-04-07 for carbonylation catalyst system.
This patent grant is currently assigned to Shell Oil Company. Invention is credited to Petrus H. M. Budzelaar, Eit Drent.
United States Patent |
5,103,043 |
Drent , et al. |
April 7, 1992 |
Carbonylation catalyst system
Abstract
A catalyst system which comprises: a) a group VIII metal
compound, and b) a monophosphine of formula ##STR1## wherein
R.sup.1 represents an aliphatic hydrocarbyl group, R.sup.2
represents an optionally substituted aromatic heterocyclic group
having 5 or 6 ring atoms of which at least one is nitrogen, which
may form part of an optionally substituted larger condensed ring
structure, and R.sup.3 independently has the meaning of R.sup.2 or
represents an optionally substituted aryl group or an acid addition
salt thereof, and their use in the carbonylation of unsaturated
compounds.
Inventors: |
Drent; Eit (Amsterdam,
NL), Budzelaar; Petrus H. M. (Amsterdam,
NL) |
Assignee: |
Shell Oil Company (Houston,
TX)
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Family
ID: |
26295047 |
Appl.
No.: |
07/672,209 |
Filed: |
March 18, 1991 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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486993 |
Mar 1, 1990 |
5028576 |
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Foreign Application Priority Data
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Mar 3, 1989 [GB] |
|
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8904860 |
Aug 18, 1989 [GB] |
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8918843 |
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Current U.S.
Class: |
560/207 |
Current CPC
Class: |
B01J
31/2409 (20130101); C07C 51/14 (20130101); C07C
67/38 (20130101); C07F 9/58 (20130101); C07F
15/0066 (20130101); C07F 15/0013 (20130101); C07C
51/14 (20130101); C07C 53/122 (20130101); C07C
67/38 (20130101); C07C 69/54 (20130101); B01J
2231/321 (20130101); B01J 2531/824 (20130101) |
Current International
Class: |
B01J
31/24 (20060101); C07C 51/14 (20060101); C07C
51/10 (20060101); C07C 67/38 (20060101); C07C
67/00 (20060101); C07F 15/00 (20060101); B01J
31/16 (20060101); C07F 9/00 (20060101); C07F
9/58 (20060101); C07C 067/36 () |
Field of
Search: |
;560/207 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0158875 |
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Apr 1984 |
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EP |
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259914 |
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Aug 1987 |
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EP |
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271144 |
|
Nov 1987 |
|
EP |
|
282142 |
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Mar 1988 |
|
EP |
|
0271144 |
|
Jun 1988 |
|
EP |
|
305012 |
|
Aug 1988 |
|
EP |
|
0305012 |
|
Mar 1989 |
|
EP |
|
386834 |
|
Oct 1989 |
|
EP |
|
Other References
Jakobsen, "NMR of Organophosphorus", J. of Molecular Spectroscopy
34, 245-256 (1970). .
Kurtev, et al., Tris(2-pyridyl)phosphine Complexes of Ruthenium(ii)
and Rhodium(i). Hydroformylation of Hex-1-ene by Rhodium Complexes,
J. of Chem. Soc., Dalton Transactions, 1980, 55-58. .
Inoguchi et al., Liganden fur extrem kurze Metall-Metall-Kontakte
in Goldkomplexen, J. Mol. Spectrose, 34(2), 245-56, 1970. .
Kurtev et al, "Tris(2-pyridyl)phosphine Complexes of Ruthenium(II)
and Rhodium(I). Hydroformylation of Hex-1-ene by Rhodium
Complexes", Journal of Chemical Society, pp. 55-58, 1979. .
Inoguchi et al, "Liganden fur extre kurze Metall-Metall-Kontakte in
Goldkoimplexen", Chem. Ber. 115, 3085-3095, 1982..
|
Primary Examiner: Killos; Paul J.
Parent Case Text
This is a division of application Ser. No. 486,993, filed Mar. 1,
1990, now U.S. Pat. No. 5,028,576.
Claims
What is claimed is:
1. A process for the carbonylation of an acetylenically or
olefinically unsaturated compound, which comprises reacting an
acetylenically or olefinically unsaturated compound with carbon
monoxide in the presence of a catalyst system which comprises:
a) a compound of divalent palladium,
b) a protonic acid having a pK.sub.a (measured at 18.degree. C. in
aqueous solution) of below 6, and
c) a monophosphine of formula ##STR6## wherein R.sup.1 represents
an aliphatic hydrocarbyl group, R.sup.2 represents a pyridyl group,
and R.sup.3 independently has the meaning of R.sup.1 or R.sup.2 or
represents an aryl group, in such an amount that the number of
moles of monophosphine per mole of protonic acid is in the range of
from 0.1 to 50.
2. The process of claim 1, in which R.sup.2 represents a pyridyl
group substituted by one or more substituents selected from
hydroxy, halogen, alkoxy, dialkylamino, mono-, di- and
trihalomethyl and alkyl groups.
3. The process of claim 1, in which R.sup.3 represents a phenyl
group.
4. The process of claim 3, in which the phenyl group is substituted
by one or more substituents selected from hydroxy, halogen, alkoxy,
dialkylamino, mono-, di- and trihalomethyl and alkyl groups.
5. The process of claim 1, in which the protonic acid has a
pK.sub.a (measured at 18.degree. C. in aqueous solution) of below
4.5.
6. The process of claim 1, in which the number of moles of
monophosphine per mole of protonic acid is in the range of from
0.25 to 4.
7. The process of claim 1, in which the catalyst system further
comprises a quinone.
8. The process of claim 1, wherein the unsaturated compound is an
alpha acetylene and the reaction is carried out with carbon
monoxide and a hydroxyl-containing compound to yield an
alpha,beta-unsaturated carboxylic acid or a derivative thereof.
9. The process of claim 8, wherein the alpha acetylene is propyne
and the hydroxyl-containing compound is methanol to yield methyl
methacrylate.
Description
FIELD OF THE INVENTION
The invention relates to a catalyst system comprising a phosphine,
to certain novel phosphines, to a process for preparing the
phosphines, and to the use of the catalyst system in the
carbonylation of olefins and acetylenes.
BACKGROUND OF THE INVENTION
Many processes are known in the art for the carbonylation of
acetylenically and olefinically unsaturated compounds. A review of
such processes is provided by J. Falbe, "New Synthesis with Carbon
Monoxide", Springer-Verlag, Berlin Heidelberg New York, 1980.
Typically, the processes involve the reaction of an olefinically
unsaturated compound with carbon monoxide and, in some cases,
hydrogen or a nucleophilic compound having a removable hydrogen
atom, in the presence of a carbonylation catalyst system. In many
instances, the carbonylation catalyst system comprises a Group VIII
metal compound and a ligand such as phosphine.
One type of catalyst system which has been disclosed in recent
years comprises a source of a Group VIII metal and a pyridyl
phosphine.
Kurti Kurtev et al, Journal of the Chemical Society, Dalton
Transactions, 1980, pages 55 to 58 disclose catalyst systems
comprising a rhodium or ruthenium compound and a pyridyl
monophosphine, and their use in the carbonylation of hex-1-ene.
European Patent Application Number EP-A1-0271144 discloses the use
of catalyst systems comprising a palladium compound, a pyridyl
monophosphine and an acid in the carbonylation of acetylenes with
hydroxyl-containing compounds. Unlike EP-A1-0259914, the broadest
definition of phosphines said to be suitable for use in the
carbonylation process is restricted to phosphines in which all
three phosphorus substituents are aromatic.
European Patent Application Number EP-A1-0282142 discloses the use
of catalyst systems comprising a palladium compound, a pyridyl
monophosphine and an acid in the carbonylation of olefins with
hydroxyl-containing compounds. Unlike EP-A1-0259914, the broadest
definition of phosphines said to be suitable for use in the
carbonylation process is restricted to phosphines in which all
three phosphorus substituents are aromatic.
European Patent Application Number EP-A2-0305012 discloses catalyst
systems comprising a palladium compound, a pyridyl diphosphine, an
acid and a quinone, and their use in the carbonylation of olefins
to afford polymers.
None of the aforementioned references discloses pyridyl
monophosphines in which the phosphorus atom has a simple, aliphatic
substituent, nor do they suggest that such phosphines may be
attractive as components for a carbonylation catalyst. Indeed, for
carbonylation catalysts other than those suitable for preparing
polymers; that is, carbonylation catalysts comprising a quinone;
the aforementioned references clearly teach away from such
phosphines.
Chem. Ber., 115 (9), 3085-95 (1982) discloses
methyl-di-2-pyridylphosphine and dimethyl-2-pyridylphosphine.
J. Mol. Spectrosc., 34 (2), 245-56 (1970) discloses
n-butyl-di-2-pyridylphosphine.
It has now been found that pyridylmonophosphines in which the
phosphorus atom has a simple, aliphatic substituent, are highly
effective as carbonylation catalyst components, especially in the
carbonylation of acetylenes.
SUMMARY OF THE INVENTION
The present invention provides a catalyst system which
comprises:
a) a group VIII metal compound, and
b) a monophosphine of formula ##STR2## wherein R.sup.1 represents
an aliphatic hydrocarbyl group, R.sup.2 represents an optionally
substituted aromatic heterocyclic group having 5 or 6 ring atoms of
which at least one is nitrogen, which may form part of an
optionally substituted larger condensed ring structure, and R.sup.3
independently is the same as R.sup.1 or R.sup.2 or represents an
optionally substituted aryl group, or an acid addition salt
thereof.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Catalyst systems according to the invention have been found to have
high activity in the carbonylation of olefins and acetylenes.
Outstandingly high reaction rates have been found in the
carbonylation of acetylenes. Furthermore, catalyst systems
according to the invention have been found to have good
selectivity. With acetylenes the catalyst systems have been found
to have good selectivity towards beta-carbonylated products, and
with olefins, they have been found to have good selectivity towards
alpha-carbonylated products. The high selectivity towards
alpha-carbonylated products with olefins is particularly
surprising.
Catalyst systems according to the invention which further comprise
a quinone have also been found to possess activity for the
carbonylation of olefinically unsaturated compounds and carbon
monoxide to afford polymers.
In the phosphines of formula I, any aliphatic hydrocarbyl group
conveniently has from one to thirty, preferably from one to twelve,
and in particular up to 5 carbon atoms. It may be an alkenyl group
such as a vinyl, allyl or butenyl group, but is preferably an alkyl
group. Preferred alkyl groups are methyl, ethyl, propyl, isopropyl,
1-butyl, 2-methyl-2-propyl(t-butyl), 1-pentyl and 1-hexyl, of which
those containing up to five carbon atoms are particularly
preferred.
In the phosphines of formula I, at least one of the ring atoms is
preferably an imino nitrogen atom.
As used herein, the term "imino nitrogen atom" means a nitrogen
atom which may be represented in the structural formula of the
aromatic, heterocyclic substituent containing it by the formula
##STR3## For example, if the aromatic substituent is a pyridyl
group, the structural formula of the aromatic substituent is
##STR4## Examples of aromatic, heterocyclic substituents containing
an imino nitrogen atom are pyridyl, pyrazinyl, quinolyl,
isoquinolyl, pyrimidinyl, pyridazinyl, cinnolinyl, triazinyl,
quinoxalinyl and quinazolinyl. Preferred substituents are pyridyl
and pyrimidyl groups.
Preferably at least one of the ring atoms is an imino nitrogen atom
which is separated from the phosphorus atom by one bridging carbon
atom. For example, if the aromatic, heterocyclic substituent is a
pyridyl group, it is preferably connected to the phosphorus atom
through the carbon atom at the 2-position in the pyridyl group.
Accordingly, examples of preferred aromatic, heterocyclic
substituents containing an imino nitrogen atom are 2-pyridyl;
2-pyrazinyl, 2-quinolyl; 1-isoquinolyl; 3-isoquinolyl;
2-pyrimidinyl; 3-pyridazinyl; 3-cinnolinyl; 2-triazinyl;
2-quinoxalinyl; and 2-quinazolinyl. 2-Pyridyl, 2-pyrimidyl and
2-triazinyl are particularly preferred. Especially good results
have been obtained when R.sup.2 is an optionally substituted
pyridyl group, in particular a 2-pyridyl group.
When R.sup.3 does not represent one of the afore-mentioned aromatic
heterocyclic groups, it represents an aliphatic hydrocarbyl group
or an optionally substituted aryl group.
An optionally substituted aryl group conveniently contains not more
than 18 carbon atoms in its ring system and is preferably an
optionally substituted phenyl group, but may be an optionally
substituted anthryl or naphthyl group.
R.sup.3 preferably represents a pyridyl group, an alkyl group or an
optionally substituted phenyl group.
Where in this specification, reference is made to "optionally
substituted", it means a group which is either unsubstituted or
substituted with one or more substituents which do not interfere
with the reaction. Suitable substituents are typically selected
from hydroxy, halogen (especially chloro and fluoro), alkoxy
(preferably C.sub.1-5 alkoxy, especially methoxy and ethoxy),
dialkylamino (especially dimethylamino and diethylamino), mono- di-
and trihalomethyl, such as trifluoromethyl, trichloromethyl and
monochloromethyl, and alkyl (preferably C.sub.1-5 alkyl group,
especially methyl, ethyl, propyl, isopropyl and tert.butyl).
Examples of substituted aromatic, heterocyclic groups are
6-methyl-2-pyridyl, 6-methoxy-2-pyridyl, 3-methyl-2-pyridyl,
4-methyl-2-pyridyl and 4,6-dimethyl-2-pyridyl.
Examples of substituted aryl groups are 4-methoxyphenyl,
3-methylphenyl and 2-fluorophenyl.
Examples of phosphines of formula (I) are:
di(n-butyl)-2-pyridylphosphine,
dimethyl 2-pyridylphosphine,
methyl phenyl-12-pyridylphosphine,
n-butyl tert.butyl 2-pyridylphosphine,
n-butyl(4-methoxyphenyl)(2-pyridyl)phosphine, and
methyl di(2-pyridyl)phosphine.
Preferred acid addition salts of the phosphines of general formula
(I) include salts with sulfuric acid; a sulfonic acid, e.g., an
optionally substituted hydrocarbylsulfonic acid such as an
optionally substituted arylsulfonic acid, e.g., benzenesulfonic
acid, p-toluenesulfonic acid or naphthalenesulfonic acid, an
optionally substituted alkylsulfonic acid, such as an alkylsulfonic
acid, e.g., methanesulfonic acid or t-butylsulfonic acid, or a
substituted aulfonic acid such as 2-hydroxypropanesulfonic acid,
trifluoromethanesulfonic acid, chlorosulfonic acid or
fluorosulfonic acid; a phosphoric acid, e.g., orthophosphoric acid,
pyrophosphoric acid, benzenephosphoric acid or toluenephosphoric
acid; a carboxylic acid, e.g., chloroacetic acid, trifluoroacetic
acid, oxalic acid or terephthalic acid; or a perhalic acid such as
perchloric acid.
Examples of Group VIII metals are iron, cobalt, nickel, ruthenium,
rhodium, palladium, iridium and platinum.
The Group VIII metal compound is preferably selected from salts of
palladium, rhodium and ruthenium, of which salts of palladium,
especially divalent palladium, are preferred. Both homogeneous and
heterogeneous metal compounds may be present, but homogeneous
compounds are preferred. Suitable compounds are the salts of nitric
acid, sulfuric acid and alkanoic acids having not more than 12
carbon atoms per molecule, e.g., acetic acid. Palladium acetate is
especially preferred. Salts of Group VIII metal with any of the
acids mentioned above in relation to the phosphines of formula (I)
are also preferred, especially palladium salts. Moreover, metal
complexes may be used, for instance, using palladium as an example,
palladium acetylacetonate, tetrakis(triphenylphosphine)palladium,
bis(tri-o-tolyphosphine)palladium acetate,
bis(diphenylphosphine)palladium acetate, or
bis(triphenylphosphine)palladium sulfate. Metal bonded on charcoal
and metal bonded to an ion-exchanger, for instance an exchange
resin containing sulfonic acid groups, are examples of suitable
heterogeneous forms of the Group VIII metal compounds.
The catalyst systems according to the invention preferably comprise
a protonic acid. It will be appreciated by those skilled in the art
that when a catalyst system according to the invention comprises an
acid addition salt of a phosphine of formula (I), the catalyst
system inevitably comprises a protonic acid.
The function of the protonic acid is to provide a source of
protons. Preferably the protonic acid is one of those referred to
above in relation to the formation of acid addition salts by the
phosphines of general formula (I). It may also be an acidic ion
exchange resin, for example a sulfonated ion exchange resin.
When the catalyst system comprises a protonic acid, the protonic
acid conveniently has a pK.sub.a (measured at 18.degree. C. in
aqueous solution) of below 6, more preferably below 4.5, e.g.,
below 4, most preferably below 2. The optimum pK.sub.a will depend
upon the particular carbonylation reaction in which the catalyst
system is to be employed.
The optimal ratio of protonic acid to phosphine will depend upon
the particular carbonylation reaction in which the catalyst system
is to be employed. Conveniently the number of moles of phosphine
per mole of protonic acid will be in the range of from 0.1 to 50,
preferably from 0.1 to 10, more preferably from 0.25 to 4.
The number of moles of phosphine of formula (I) per gram atom of
Group VIII metal in the catalyst system according to the invention
is not critical. It will depend upon the particular Group VIII
metal and the particular carbonylation reaction. Preferably the
number of moles of phosphine per gram atom of palladium is in the
range of from 1 to 1,000, more preferably from 2 to 500, for
example from 10 to 100.
The catalyst system according to the invention is constituted in a
liquid phase. The liquid phase may conveniently be formed by one or
more of the reactants with which the catalyst system is to be used.
Alternatively, it may be formed by a solvent. It may also be formed
by one of the components of the catalyst system.
The catalyst systems according to the invention may be homogeneous
or heterogeneous. Most preferably they are homogeneous.
The catalyst systems according to the invention may be generated by
any convenient method. Thus they may be prepared by combining a
Group VIII metal compound, a phosphine of general formula (I) and,
if appropriate, a protonic acid in a liquid phase. Alternatively,
they may be prepared by combining a Group VIII metal compound and
an acid addition salt of general formula (I) in a liquid phase.
Alternatively, they may be prepared from a Group VIII metal
compound which is a complex of a Group VIII metal with a phosphine
of general formula (I), and/or a protonic acid in a liquid
phase.
As has been stated above three phosphines of general formula (I)
have been disclosed in Chem. Ber., 115 (9), 3085-95 (1982) and J.
Mol. Spectrosc., 34 (2), 245-56 (1970). The remaining phosphines of
general formula (I), are believed to be novel. Accordingly, the
invention also provides a phosphine of general formula (I) or an
acid addition salt thereof, as defined above, except for
methyl-di-2-pyridyl phosphine, dimethyl-2-pyridyl phosphine, and
n-butyl-di-2-pyridyl phosphine.
The phosphines of general formula (I) may be prepared by a process
which comprises reacting a compound of general formula: ##STR5## in
which M.sup.1 represents either a metal atom or a leaving atom or
group and R.sup.2.spsp.a and R.sup.3.spsp.a represent two of
R.sup.1, R.sup.2 and R.sup.3 as defined above, with an appropriate
compound of general formula:
in which M.sup.2 represents either a metal atom or a leaving atom
or group and R.sup.1.sbsp.a represents the remainder from R.sup.1,
R.sup.2 and R.sup.3 optionally followed by forming an acid addition
salt.
It will be appreciated that when M.sup.1 represents a metal atom,
the appropriate compound of general formula (III) is one wherein
M.sup.2 represents a leaving atom or group. Similarly when M.sup.1
represents a leaving atom or group, the appropriate compound of
general formula (III) is one wherein M.sup.2 represents a metal
atom.
A metal atom represented by M.sup.1 or M.sup.2 may be any main
group metal, for example an alkali metal, such as lithium, sodium
or potassium; an alkaline earth metal, such as magnesium; zinc;
cadmium; mercury; aluminum; gallium; indium; thallium; tin or lead.
Preferably a metal atom is an alkali metal atom.
The leaving atom or group is preferably a halogen atom, most
preferably a chlorine or bromine atom.
Preferably M.sup.2 represents a halogen atom.
Preferably R.sup.1.spsp.a represents R.sup.1.
The reaction between the compound of general formula (II) with the
compound of general formula (III) may conveniently be effected in
the presence of a solvent. Suitable solvents include liquid ammonia
and ethers such as tetrahydrofuran or diethyl ether, or
hydrocarbons such as benzene or toluene.
The process is conveniently effected at a temperature in the range
of from -100.degree. C. to 100.degree. C., preferably from
-80.degree. C. to 0.degree. C.
An acid addition salt may conveniently be formed by contacting a
phosphine of general formula (I) with an appropriate acid,
preferably in the presence of a solvent.
Compounds of formula (III) wherein M.sup.2 represents a metal atom
may be prepared from the corresponding compounds wherein M.sup.2
represents a leaving atom or group, for example a chlorine, bromine
or iodine atom, by reaction with a metal alkyl, for example butyl
lithium.
Compounds of formula (II) wherein M.sup.1 represents a chlorine or
bromine atom, may be prepared in situ from corresponding di- and
tri-chloro or bromophosphines by reaction with an appropriate metal
compound of formula (III).
Compounds of formula (II) wherein M.sup.1 represents an alkali
metal, such as lithium, may conveniently be prepared by reacting a
compound of formula (II) wherein M.sup.1 represents a pyridyl group
with an alkali metal pyridine, alkyl, aryl or hydride. On occasion,
it may be convenient to generate such compounds of formula (II) in
situ, for example by reacting a halopyridine with an alkali metal
alkyl to form a mixture of an alkali metal pyridine and a
haloalkane, and then reacting the mixture with a bis-or
tris-pyridylphosphine to afford initially the desired alkali metal
alkylpyridylphosphine by reaction of the phosphide with the
haloalkane. The preparation of such compounds of formula (II) is
the subject of British Patent Application Number 8923683.
As has been stated above, it has been found that catalyst systems
according to the invention have good activity in the carbonylation
of acetylenically and olefinically unsaturated hydrocarbons.
Accordingly, the invention further provides the use of a catalyst
system as defined hereinbefore in the carbonylation of an
acetylenically or olefinically unsaturated hydrocarbon.
According to a further aspect, the present invention provides a
process for the carbonylation of an acetylenically or olefinically
unsaturated compound, which comprises reacting an acetylenically or
olefinically unsaturated compound with carbon monoxide in the
presence of a catalyst system as defined hereinabove.
As is well known by those skilled in the art, a very large variety
of processes are known for the carbonylation of acetylenically and
olefinically unsaturated compounds. Such processes can be divided
into several types of reactions, depending upon the starting
materials. Examples of such reactions are hydroformylation, the so
called Reppe reaction, in which an unsaturated compound is reacted
with carbon monoxide and a nucleophilic compound having a removable
hydrogen atom; and copolymerization of an unsaturated compound with
carbon monoxide.
The acetylenically or olefinically unsaturated compound is
preferably an alpha olefin or acetylene.
An olefinically unsaturated compound is preferably a substituted or
unsubstituted alkene or cycloalkene having from 2 to 30, preferably
from 3 to 20 carbon atoms per molecule.
An acetylenically unsaturated compound is preferably a substituted
or unsubstituted alkyne having from 2 to 20, especially from 3 to
10 carbon atoms per molecule.
The acetylenically or olefinically unsaturated compound may contain
one or more acetylenic or olefinic bonds, for example one, two or
three acetylenic or olefinic bonds.
An olefin or acetylene may be substituted by, for example, a
halogen atom, a cyano group, an acyl group such as acetyl, an
acyloxy group such as acetoxy, an amino group such as dialkylamino,
an alkoxy group such as methoxy, a haloalkyl group such as
trifluoromethyl, a haloalkoxy group such as trifluoromethoxy, an
amido group such as acetamido, or a hydroxy group. Some of these
groups may take part in the reaction, depending upon the precise
reaction conditions. For example, lactones may be obtained by
carbonylating certain acetylenically unsaturated alcohols, for
example 3-butyn-1-ol, 4-pentyn-1-ol or 3-pentyn-1-ol. Thus
3-butyn-1-ol may be converted into a
.alpha.-methylene-.gamma.-butyrolactone.
Examples of alkynes are: ethyne, propyne, phenylacetylene,
1-butyne, 2-butyne, 1-pentyne, 1-hexyne, 1-heptyne, 1-actyne,
2-octyne, 4-actyne, 1,7-octadiyne, 5-methyl-3-heptyne,
4-propyl-2-pentyne, 1-nonyne, benzylethyne and
cyclohexylethyne.
Examples of alkenes are: ethene, propene, phenylethene, 1-butene,
2-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 2-octene,
4-octene, cyclohexene and norbornadiene.
The acetylenically or olefinically unsaturated compound can be both
an acetylene and an olefin, for example as in
3-methyl-but-3-ene-1-yne.
The unsaturated compound may be carbonylated alone or in the
presence of other reactants, for example, hydrogen or a
nucleophilic compound having a removable hydrogen atom. An example
of a nucleophilic compound having a removable hydrogen atom is a
hydroxyl-containing compound.
A hydroxyl-containing compound is preferably an alcohol, water or a
carboxylic acid.
An alcohol used may be aliphatic, cycloaliphatic or aromatic and
may carry one or more substituents. The alcohol preferably
comprises up to 20 carbon atoms per molecule. It may be, for
example, an alkanol, a cycloalkanol or a phenol. One or more
hydroxyl groups may be present, in which case several products may
be formed, depending on the molar ratio of the reactants used.
Examples of alkanols include methanol, ethanol, 1-propanol,
2-propanol, 1-butanol, 2-butanol, 2-methylpropan-1-ol, and
2-methylpropan-2-ol.
Other examples of alcohols include polyvalent alcohols, in
particular lower sugars such as glucose, fructose, mannose,
galactose, sucrose, aldoxose, aldopentose, altrose, allose, talose,
gulose, idose, ribose, arabinose, xylose, lyxose, erythrose or
rhreose, cellulose, benzyl alcohol,
2,2-bis(hydroxymethyl)-1-butanol, stearyl alcohol, cyclohexanol,
ethylene glycol, 1,2-propanediol, 1,4-butanediol,
polyethyleneglycol, glyerol and 1,6-hexanediol.
The process according to the present invention may be carried out
using a wide variety of carboxylic acids. For example, the
carboxylic acids may be aliphatic, cycloaliphatic or aromatic and
may carry one or more substituents, such as those named in
connection with the acetylenically and olefinically unsaturated
compounds.
Carboxylic acids preferably used in the process according to the
invention include those containing up to 20 carbon atoms. One or
more carboxylic acid groups may be present, thus allowing various
products as desired, depending on the molar ratio of the reactants
used. The carboxylic acids may, for example, be alkanecarboxylic
acids or alkenecarboxylic acids. Examples of carboxylic acids are:
formic acid, acetic acid, propionic acid, n-butyric acid,
isobutyric acid, pivalic acid, n-valeric acid, n-capronic acid,
caprylic acid, capric acid, lauric acid, myristic acid, palmitic
acid, stearic acid, benzoic acid, o-phthalic acid, m-phthalic acid,
terephthalic acid and toluic acid. Examples of alkenecarboxylic
acids are acrylic acid, propiolic acid, methacrylic acid, crotonic
acid, isocrotonic acid, oleic acid, maleic acid, fumaric acid,
citraconic acid and mesaconic acid.
It will be appreciated that the unsaturated hydrocarbon and the
hydroxyl-containing compound may be the same compound.
When an acetylenically unsaturated compound is reacted with water
and carbon monoxide, an alpha,beta-unsaturated carboxylic acid is
formed. If an alcohol is used instead of water, an
alpha,beta-unsaturated carboxylic ester is formed. If a carboxylic
acid is used instead of water, an alpha,beta-unsaturated anhydride
is formed. The alpha,beta-unsaturated product may undergo further
reaction depending upon the reaction conditions employed.
It has been found that catalyst systems according to the invention
are particularly useful for the carbonylation of alpha acetylenes
with hydroxyl-containing compounds.
Accordingly, in a preferred aspect, therefore, the invention
provides a process for the preparation of an
alpha,beta-olefinically unsaturated compound, which comprises
reacting an alpha acetylene with carbon monoxide and a
hydroxyl-containing compound in the liquid phase in the presence of
a carbonylation catalyst system as hereinbefore described.
In the process, the carbonylation catalyst system is preferably a
palladium catalyst as described above, namely a catalyst system
which comprises:
a) a palladium compound,
b) a phosphine of general formula (I), and
c) a protonic acid.
It is not essential to use a separate solvent in the process
according to the invention.
A large excess of the product or of one of the reactants, for
example an alcohol, can often form a suitable liquid phase. In some
cases, however, it may be desirable to use a separate solvent. Any
inert solvent can be used for that purpose. Said solvent may, for
example, comprise sulfoxides and sulfones, for example
dimethylsulfoxide, diisopropylsulfone or tetrahydrothiophene-2,
2-dioxide (also referred to as sulfolane), 2-methylsulfolane,
3-methylsulfolane, 2-methyl-4-butylsulfolane; aromatic hydrocarbons
such as benzene, toluene, xylenes; esters such as methylacetate and
butyrolactone; ketones such as acetone or methyl isobutyl ketone,
ethers such as anisole, 2,5,8-trioxanonane (also referred to as
diglyme), diphenyl ether and diisopropyl ether, and amides such as
N,N-dimethylacetamide or N-methylpyrrolidone.
The process according to the present invention is conveniently
effected at a temperature in the range of from 10.degree. C. to
200.degree. C., in particular from 20.degree. C. to 130.degree.
C.
The process according to the invention is preferably effected at a
pressure of from 1 bar to 70 bar. Pressures higher than 100 bar may
be used, but are generally economically unattractive on account of
special apparatus requirements.
The molar ratio of the hydroxyl-containing compound to the
unsaturated hydrocarbon may vary between wide limits and generally
lies within the range of 0.01:1 to 100:1.
The quantity of the Group VIII metal is not critical. Preferably,
quantities are used within the range of 10.sup.-7 to 10.sup.-1 gram
atom Group VIII metal per mol of unsaturated compound.
The carbon monoxide required for the process according to the
present invention may be used in a practically pure form or diluted
with an inert gas, for example nitrogen. The presence of more than
small quantities of hydrogen in the gas stream is undesirable on
account of the hydrogenation of the unsaturated hydrocarbon which
may occur under the reaction conditions. In general, it is
preferred that the quantity of hydrogen in the gas stream supplied
is less than 5 vol %.
Another reaction which is catalyzed by catalyst systems according
to the invention, and which may be regarded as a carbonylation, is
the preparation of linear, alternating polyketone polymers by
copolymerizing olefinically unsaturated compounds with carbon
monoxide.
When polymers are desired, the catalyst system used preferably
comprises a quinone. Examples of quinones are optionally
substituted benzoquinones, naphthaquinones and orthoquinones.
Benzoquinones are preferred especially 1,4-benzoquinone. The amount
of quinone used is conveniently from 1 to 1,000 moles per gram atom
of Group VIII metal (e.g. palladium), preferably from 10-5,000.
The invention will be described further by the following Examples
which are illustrative in purpose and are not to be construed as
limiting the scope of the invention. The term "selectivity" as used
in this specification and these examples, is defined as
(a/b).times.100%, wherein "a" is the molar quantity of
acetylenically or ethylenically unsaturated compound converted into
the desired carbonylated compound, and "b" stands for the total
molar quantity of unsaturated compound that has been converted. The
term "reaction time" refers to the period during which reaction
takes place, as evidenced by a decreasing autoclave pressure, and
does not comprise an induction period which may precede the
reaction period.
EXAMPLES
All preparations of phosphines were carried out under an atmosphere
of argon, solvents (tetrahydrofuran, diethylether) were distilled
under argon from sodium benzophenone prior to use. Unless otherwise
stated, the allene content of any propyne used in the following
examples was less than 0.2%.
EXAMPLE 1
Preparation of di(n-butyl)-2-pyridyl phosphine
To a magnetically stirred solution of 2.5 g phenyl(2-pyridyl).sub.2
P in 20 mol tetrahydrofuran, cooled to -80.degree. C. was added in
the course of 10 min 5.9 ml of a 1.6M solution of n-butylLi in
hexane. The resulting deep-red solution was allowed to warm to room
temperature, and analysis of the solution by .sup.31 P NMR showed
it to contain the phosphide (n-butyl)(2-pyridyl)-PLi as the only
phosphorus-containing compound (.delta..sub.p =-16.3 ppm).
The solution was cooled to -40.degree. C. and a solution of 1.3 g
1-bromobutane in 10 ml tetrahydrofuran was added. The mixture was
again warmed to room temperature, the solvents were removed in
vacuo, and 25 ml of diethylether and 10 ml of water were added.
After 10 min of stirring, the organic layer was separated and the
water layer was extracted with 10 ml of ether. The organic layers
were combined and the solvent was removed in vacuo (66 Pa). The
resulting light-yellow liquid was analyzed by .sup.1 H, .sup.13 C
and .sup.31 P NMR and shown to consist of a 1:1 (molar ratio)
mixture of 2-phenylpyridine and (n-butyl).sub.2 (2-pyridyl)P
(.delta..sub.p =-19.5 ppm).
EXAMPLE 2
Preparation of dimethyl 2-pyridyl phosphine and
methylphenyl-2-pyridyl phosphine
The method of Example 1 was repeated, except that a 1.6M solution
of methyl Li in diethylether was used instead of the n-butyl Li
solution, and 1.3 g iodomethane instead of the bromobutane. The
reaction product was a mixture of (methyl).sub.2 (2-pyridyl)P,
methyl phenyl 2-pyridylP and 2-phenyl pyridine in the approximate
ratio 70:30:60, from which the (methyl).sub.2 (2-pyridyl)P was
isolated by distillation.
The physical characteristics of the products were .delta..sub.p
=-41.2 ppm (dimethyl-2-pyridylphosphine) and .delta..sub.p =-24.1
ppm (methylphenyl-2-pyridylphosphine).
EXAMPLE 3
Preparation of n-butyl tert-butyl 2-pyridyl phosphine
The method of Example 1 was repeated, except that 5.6 ml of a 1.7M
solution of t-butyl Li in pentane was used instead of the n-butyl
Li solution. The final product was identified as n-butyl t-butyl
2-pyridyl P by NMR analysis (.delta..sub.p =7.4 ppm).
EXAMPLE 4
Preparation of dimethyl 2-pyridylphosphine
The method of Example 2 was repeated, except that 1.91 g
methyl(2-pyridyl.sub.2 P and only 0.7 g iodomethane were used.
Workup as described in Example 1 afforded dimethyl 2-pyridyl
phosphine, which was further purified by distillation (65% yield).
(.delta..sub.p =-41.2 ppm).
EXAMPLE 5
Preparation of n-butyl(4-methoxyphenyl)(2-pyridyl)phosphine)
All manipulations were carried out in an inert atmosphere (nitrogen
or argon). Solvents were dried and distilled prior to use. 18 ml of
a 1.6M n-butyl lithium solution in hexane was added to 30 ml
diethyl ether, and the mixture was cooled to -40.degree. C. To the
stirred mixture was added in the course of 20 minutes a solution of
4.6 g 2-bromopyridine in 15 ml diethyl ether; during this addition,
the temperature was kept at -40.degree. C. After the addition, the
temperature was raised to -5.degree. C., kept there for 5 minutes,
and then lowered again to -40.degree. C. The resulting solution was
added to a cooled (-40.degree. C.) solution of 7.6 g
4-methoxyphenyl-bis(2-pyridyl)-phosphine in 30 ml THF. The mixture
was warmed to room temperature. After stirring for 10 minutes, the
solvents were removed in vacuo. Water (25 ml) and dichloromethane
(25 ml) were added. After 5 minutes of vigorous stirring, the
dichloromethane layer was separated. The water layer was extracted
with two 25 ml portions of dichloromethane, the organic fractions
were combined, and the solvent removed in vacuo. The residue was
distilled, giving 4.7 g (60%) of
(n-butyl)(4-methoxyphenyl)(2-pyridyl)phosphine as a yellowish
liquid. The product was characterized by .sup.31 P NMR:
.delta..sub.p =-14.9 ppm.
In this experiment, n-butyl lithium is believed to react with
2-bromopyridine to afford a mixture of n-butylbromide and 2-pyridyl
lithium. Then the 2-pyridyl lithium reacts with
4-methoxy-bis(2-pyridyl)phosphine to afford
4-methoxyphenyl(2-pyridyl)lithium phosphide (and 2,2'-bipyridine).
The lithium phosphide then reacts with n-butylbromide to afford
(n-butyl)(4-methoxyphenyl)(2-pyridyl)phosphine.
EXAMPLE 6
Preparation of methyl di(2-pyridyl)phosphine)
All manipulations were carried out in an inert atmosphere (nitrogen
or argon). Solvents were dried and distilled prior to use. 36 ml of
a 1.6M n-butyl lithium solution in hexane was added to 40 ml
diethyl ether, and the mixture was cooled to -40.degree. C. To the
stirred mixture was added in the course of 20 minutes a solution of
9.2 g 2-bromopyridine in 15 ml diethyl ether; during this addition,
the temperature was kept at -40.degree. C. After the addition, the
temperature was raised to -5.degree. C., kept there for 5 minutes,
and then lowered again to -40.degree. C. A solution of 3.4 g
methyldichlorophosphine in 15 ml diethyl ether was added to the
stirred mixture. After the addition, the mixture was warmed to room
temperature, the solvents were removed in vacuo, and 50 ml water
and 50 ml dichloromethane were added. After 5 minutes of vigorous
stirring, the dichloromethane layer was separated. The water layer
was extracted with two 50 ml portions of dichloromethane, the
organic fractions were combined, and the solvent removed in vacuo.
The residue was distilled, giving 4.0 g (68%) of
methyl-bis(2-pyridyl)-phosphine as a yellowish liquid. The product
was characterized by .sup.31 P NMR: .delta..sub.p =-20.5 ppm.
EXAMPLE 7
Preparation of methyl methacrylate by carbonylation of propyne and
methanol
Methyl methacrylate was prepared as follows. A 300 ml magnetically
stirred Hastelloy (Hastelloy is a registered trade mark) autoclave
was successively filled with 0.025 mmol palladium(II) acetate, 1
mmol butyl(4-methoxyphenyl)(2-pyridyl)phosphine, 2 mmol
p-toluenesulfonic acid, 30 ml methanol and 30 ml
N-methylpyrrolidone (solvent). Air was evacuated from the
autoclave, whereupon 25 ml of propyne was added. Subsequently,
carbon monoxide was introduced to a pressure of 60 bar. The
autoclave was sealed and heated to a temperature of 50.degree. C.
After a reaction time of 11/2 hours at 50.degree. C. a specimen of
the contents was analyzed by means of gas-liquid chromatography.
The selectivity of the conversion of propyne to methyl methacrylate
was found to be 98.9%, while the mean conversion rate was
calculated to be 20,000 mol propyne/gramatom Pd/hours.
EXAMPLE 8
Preparation of methyl methacrylate by carbonylation of propyne and
methanol
Example 1 was repeated, but with the following differences:
a) the ligand used was methyldi(2-pyridyl)phosphine instead of
butyl(4-methoxyphenyl)(2-pyridyl)phosphine, and
b) the reaction temperature was 80.degree. C. instead of 50.degree.
C.
The selectivity of the conversion of propyne to methyl methacrylate
was found to be 99.1%, while the mean conversion rate was
calculated to be 12,500 mol propyne/gramatom Pd/hour.
COMPARATIVE EPERIMENT A
Example 8 was repeated, but with the following differences:
a) the ligand used was phenyldi(2-pyridyl)phosphine instead of
methyldi(2-pyridyl)phosphine, and
b) the reaction time was 2 hours instead of 11/2 hours.
The selectivity of the conversion of propyne to methyl methacrylate
was found to be 98.3%, while the mean conversion rate was
calculated to be 8,000 mol propyne/gramatom Pd/hour. The
replacement of an aryl group by an aliphatic group in the organic
phosphine appears to have a beneficial effect.
EXAMPLE 9
Preparation of propionic anhydride by carbonylation of ethene and
propionic acid
Propionic anhydride was prepared as follows. A 300 ml magnetically
stirred Hastelloy (Hastelloy is a registered trade mark) autoclave
was successively filled with 0.1 mmol palladium(II) acetate, 4 mmol
butyl(4-methoxyphenyl)(2-pyridyl)phosphine, 2 mmol
p-toluenesulfonic acid, 20 ml propionic acid and 50 ml anisole
(solvent). Air was evacuated from the autoclave, whereupon ethene
was blown in until a pressure of 20 bar was reached. Subsequently,
carbon monoxide was introduced to a partial pressure of 30 bar. The
autoclave was sealed and heated to a temperature of 90.degree. C.
After a reaction time of 5 hours at 90.degree. C. a specimen of the
contents was analyzed by means of gas-liquid chromatography. The
selectivity of the conversion of ethene to propionic anhydride was
found to be 99.5%, while the mean conversion rate was calculated to
be 300 ml ethene/gramatom Pd/hour.
EXAMPLE 10
Preparation of methyl propionate by carbonylation of ethene and
methanol
Methyl propionate was prepared as follows. Example 9 was repeated
except for the difference that 50 mol methanol was added instead of
the 20 ml propionic acid and 50 ml anisole. The selectivity of the
conversion of ethene to methyl propionate was found to be 99.5%,
while the mean conversion rate was calculated to be 200 mol
ethene/gat Pd/hr.
EXAMPLE 11
Preparation of a linear alternating CO/ethane copolymer using a
quinone-containing catalyst
A linear, alternating CO/ethene copolymer was prepared as follows.
A 250 ml magnetically stirred Hastelloy (Hastelloy is a registered
trade mark) autoclave was charged with a solution of 50 ml methanol
and a catalyst system comprising 0.1 mmol palladium(II) acetate, 3
mmol butyl(4-methoxyphenyl)(2-pyridyl)phosphine, 2 mmol
p-toluenesulfonic acid, and 20 mmol p-benzoquinone. Air was
evaculated from the autoclave, whereupon ethene was blown in until
a pressure of 20 bar was reached. Subsequently, carbon monoxide was
introduced to a partial pressure 30 bar. The autoclave was sealed
and heated to a temperature of 110.degree. C. After a reaction time
of 3 hours at 110.degree. C. the polymerization was terminated by
cooling to room temperature and then releasing the pressure. The
polymer formed was filtered off, washed with methanol and dried in
vacuo at room temperature. The selectivity of the conversion of
ethene to copolymer was 100.degree., and the yield was 0.9 g of
copolymer, corresponding to a mean rate of 30 g copolymer/g Pd/hr.
By means of .sup.13 C-NMR analysis it was established that the
carbon monoxide/ethene copolymer prepared had a linear alternating
structure and therefore consisted of units of the formula
--CO--(C.sub.2 H.sub.4)--.
* * * * *